Defensive publication

ABSTRACT

A MAGNETIC RECORDING MATERIAL, WHICH COMPRISES A MOLECULARLY ORIENTED AND HEAT SET POLYESTER FILM BASE HAVING A COATING COMPRISING VINYL CHLORIDE POLYMER PARTICLES ON ONE SURFACE AND A MAGNETIC COATING ON THE OTHER SURFACE, THE VINYL CHLORIDE POLYMER PARTICLE COATING HAVING A COAT WEIGHT OF 0.01 TO 1.4 MG. DM. -2 AND THE AVERAGE SIZE OF A MADE BY COATING THE SURFACE OF THE POLYESTER FILM BASE WITH THE VINYL CHLORIDE POLYMER PARTICLES DURING OR AFTER THE ORIENTATION AND HEAT SETTING. PREFERABLY THE FINAL COAT WEIGHT OF THE VINYL CHLORIDE POLYMER PARTICLE COATING IS FROM 0.05 TO 0.25 MG. DM. -2 AND THE AVERAGE SIZE OF AGGLOMERATED VINYL CHLORIDE POLYMER PARTICLES IN THE FINAL COATING IS FORM 10 TO 15 MICRONS.

DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at therequest of the applicant or owner in accordance with the Notice of Dec.16, 1969, 869 O.G. 687. The abstracts of Defensive Publicationapplications are identified by diwnctly numbered series and are arrangedchronologically. The heading of each abstract indicates the number ofpages of specification, including claims and sheets of drawingscontained in the application as originally filed. The files of theseapplications are available to the public-for inspection and reproductionmay be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to themerits of alleged invention. The Patent Oiilce makes no assertion as tothe novelty of the disclosed subject matter,

PUBLISHED MARCH 5, 1974 T920,016 MAGNETIC RECORDING MATERIALS ArthurJohn Holloway, Bengeo, and Graham George Turner, Sandy, England,assignors to Imperial Chemical Industries Limited, London, England FiledAug. 21, 1973, Ser. No. 390,303 Claims priority, application GreatBritain, Sept. 1, 1972, 40,672/72 Int. Cl. H01f 10/00 US. Cl. 117--235No Drawing. 14 Pages Specification A magnetic recording material, whichcomprises a molecularly oriented and heat set polyester film base havinga coating comprising vinyl chloride polymer particles on one surface anda magnetic coating on the other surface, the vinyl chloride polymerparticle coating having a coat weight of 0.01 to 1.4 mg. dmr Thematerial is made by coating the surface of the polyester film base withthe vinyl chloride polymer particles during or after the orientation andheat setting. Preferably the final coat weight of the vinyl chloridepolymer particle coating is from 0.05 to 0.25 mg. (1m.- and the averagesize of agglomerated vinyl chloride polymer particles in the finalcoating is from 10 to 15 microns.

